Data Sharing Scheme for Dynamic Groups in the Cloud

Abstract

Users benefit from cloud computing, and can achieve an efficient and economical approach to sharing data among cloud group members with low-maintenance characters and low management costs. In the meantime, we must provide security guarantees to share data files because they are outsourced. Unfortunately, because of the frequent change of membership, sharing data while maintaining privacy is still a difficult issue, especially for an unreliable cloud due to the attack of collusion. Moreover, for existing schemes, key distribution security depends on the secure communication channel, however, assuming that this channel is a strong and difficult enforcement practice. In this paper, we propose a secure data sharing plan for dynamic members. First, we suggest a secure way to distribute keys without any secure connection channels, and users can get their own keys securely from the group manager. Second, our system can achieve strict access control, a user in the group who can use the source in the cloud and cancel users can not access the cloud again after revocation. Third, we can protect the schema from an attack of collusion, which means that users who have been revoked can not get the original data file even if they are plotting with the unreliable cloud. In our approach, by taking advantage of the multi-border function, we can achieve a secure user uninstallation system. Finally, our plan can perform well, which means that previous users do not need to update their own status keys if a new user joins the group or the user is revoked from the group.